Supported aluminum chloride catalyst



Oct. 21, 1947. J. w. LATCHUM, JR., El AL 2,429,232

SUPPORTED ALUMINUM CHLORIDE CATALYST Original Filed June 6, 1944BHLBBANOD NOLLVZIHBWOSI MEANS FOR SUBLIMING ALCL 3 INVENTORS J w.LATCHUM .m. BY A.D.\ PICKE TT 6.8. EVANS Patented Och 21, 1947 SUPPORTEDGAA John W. Latchum, Jr., Bartlesville, Okla, and Armand D. Pickett,Odessa, and Gerald B. Evans, Kingsville, Tex assignors to PhillipsPetroleum Company, a corporation of Delaware Original application June6, 1944, Serial No.

538,998. Divided and this application 4, 1946, Serial No. 645,472

4 Claims. (01. 252-211) 1 I a w This invention relates to isomerizationof normal parailins such as butane, pentane or hexane, to isoparafiinsby means of a catalyst comprising aluminum chloride and in the presenceof hydrogen chloride as a promoter. It is especially applicable to theisomerization of normal butane to isobutane which is of major importanceat the present time;

The principal object of the present invention 7 is to provide animproved paraflin isomerization process. Another object is to providesuch a process wherein there is used a catalyst comprising a novel typeof carrier which is cheap and easily available and which gives resultscomparable with the best catalyst heretofore employed. Numerous otherobjects will more fully hereinafter appear.

The accompanying drawing which is self-explanatoiyportraysonearrangement of equipment useful for carrying out the present invention.

The isomerization of normal butane to isobutane by means of aluminumchloride in the presence of hydrogen chloride as an activator has becomean important commercial process and our invention will be described withparticular reference thereto. The aluminum chloride has been used byitself ordinarily in the form of relatively- Group I of the PeriodicSystem. Only two of these chlorides, namely, sodium chloride andpotassium chloride, are sufficiently cheap or readily available towarrant serious consideration for commercial application.

We have found that a catalyst consisting of aluminum chloride supportedon a carrier consisting of granular sodium or potassium chloride ishighly effective in theisomerization of normal parafins. In actual testswe have demonstrated that rock salt as a support for aluminum chloridegives results comparable with Porocel. This was unexpected since it wasnot foreseen that a hard crystalline non-porous water-soluble materialsuch as sodium chloride would efiect these results. In fact sodiumchloride as a carrier is far superior to pumice which is in physical andchemical aspects much more like Porocel than salt.

The catalyst of the present invention consists OFFICE.

February of a major proportion of granular sodium or potassium chloride,the former being preferred, and a minor proportion of aluminum chlorideon the surfaces thereof. The amount df aluminum chloride should notexceed the weight of the carrier. It is preferred that the aluminumchloride range from 1 to 40 per cent by weight or the salt carrier. Arange of from 1 to25 weight per cent may be more commonly employed.

The aluminum chloride is actually supported as such on the surfaces ofthe granules of sodium or potassium chloride. So far as can beascertained, there is no mingling of the aluminum chloride with thesodium or potassium chloride which would cause it to lose its identity.7

A preferred mode of preparation of the catalyst is to sublime thealuminum chloride onto the sodium or potassium chloride. For example,the granular carrier may be deposited in the converter whereupon astream of aluminum chloride vapors is passed therethrough under suchconditions well within the skill of the art that the aluminum chlorideis condensed in the form of a thin layer on the surfaces of the carrier.The stream of aluminum chloride vapors may be the vaporous eflluent froman isomerization chamber which effluent commonly carries I volatilizedaluminum chloride, in which case the bed of granular sodium chlorideacts as a "guard chamber removing the aluminum chloride from theisomerization effluent. Under such. circumstances, additionalisomerization actually takes place in the "guard chamber." Thereafterthe converter which was used as a guard chamber during formation of thecatalyst may be used as a primary chamber. Thus the sodium chloride maybe employed in a primary, secondary, or guard chamber."

It is often preferred however to eflect sublimation of aluminum chlorideonto the sodium chloride by placing the latter in the converter andemploying a subliming chamber through which hot normal paraflln feed isdiverted on its way through the converter in the manner shown in thedrawing. Ordinarilythe hydrogen chloride feed is discontinued while thecatalyst is beingv made in this way. When a suitable amount of aluminumchloride has been thus deposited onto the surfaces of the sodiumchloride granules, the subliming unit is bypassed and the converterplaced on-stream in the usual way. The subliming unit is usedperiodically whenever it is desired to replenish the aluminum chlorideon the carrier. 3

Following are examples of actual butane isomer- Examples I A mixture ofhydrocarbons consisting essentially of isobutane and normal butane,hydrogen chloride and some volatilized aluminum chloride and issuingfrom a primary chamber was passed through a secondary chamber containingaluminum chloride supported on rock salt and analyzselected from theleft-hand column of Group I ing 1.3 per cent aluminum chloride, 94.2 percent sodium chloride. 0.67 percent calcium sulfate, 0.32 per centmagnesium sulfate, 0.14 per cent magnesium chloride and 3.37 per centinsoluble material. Two separate and distinct runs were made.

The inlet temperature was 234 F. in the first and 232 F. in the secondrun. The outlet temperature was 194 F. in the flrst-and 212 F. in thesecond run. The pressure in each run was 190 p. s. i. The per cent byvolume of hydrogen chloride in the feed'was 7.6 per cent in the firstand 5.3 per cent in the second run. The isobutane content of thehydrocarbons was increased from 28.5 to 40 per cent in the first run andfrom 6.5 per cent to per cent in the second run. Each run was for aperiod of three days.

From the foregoing it will be seen that the present invention provides anovel and improved method of isomerizing normal paramns to isoparafflns.The carrier and especially sodium chorlde is cheap and readilyavailable. It performs practically as well as "Porocel" which is nowmost widely used. The carrier does not melt down thus rendering use ofhigh temperatures feasible. The carrier operates well even though thepercentage of A1013 is very low. The carrier of the present inventionworks as well as Porocel in the secondary chamber whereas pumice givesno appreciable conversion when used under the same conditions. Numerousother advantages of the present invention will be apparent to thoseskilled in the art.

This application is a division of our prior an copending applicationSerial No. 538,998, filed ofthe Periodic System, the percentage byweight of said aluminum chloride based on the weight of said granularchloride ranging from 1 to 40 per cent, there. being no ascertainablemingling of th e aluminum chloride with said granular chloride.

2. As a new article of manufacture, a catalyst consisting of aluminumchloride supported as such on the surfaces of the granules of a carrierconsisting of granular sodium chloride, the percentage by weight of saidaluminum chloride based on the weight of said sodium chloride rangingfrom 1 to 40 per cent, there being no ascertainable mingling or thealuminum chloride with said sodium chloride.

3. As a. new article of manufacture, a catalyst consisting of aluminumchloride supported as such on the surfaces of the granules of a carrierconsisting of a granular chloride of a metal selected from the left-handcolumn of Group I of the Periodic System, the percentage by weight ofsaid aluminum chloride based on the weight of said granular chlorideranging .from 1 to 25 per cent, there being no ascertainable mingling ofthe aluminum chloride with said granular chloride.

June 6, 1944, which is directed to the herein-de- 4 1. As a new articleor manufacture, a catalyst consisting of aluminum chloride supported assuch op the surfaces of the granules of a carrier consisting of agranular chloride of a metal 4. As a new article of manufacture, acatalyst consisting of aluminum chloride supported as such on thesurfaces of the granules of a carrier consisting of granular sodiumchloride, the percentage by weight of said aluminum chloride based onthe weight of said sodium chloride ranging from 1 to 25 per cent, therebeing no ascertainable mingling of the aluminum chloride with saidsodium chloride.

JOHN .W. LATCHUM, JR. ARMANI) D. PICKETT. GERALD B. EVANS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,342,124 Danforth Feb. 22, 19441,716,372 Downs June 11, 1929 2,301,615 Chenicek et al. Nov, 10, 19422,279,292 Cheney Apr. 14, 1942 2,040,658 Kuentzel et al. May 12, 19362,271,299 Ipatieff et al Jan. 27, 1942

